In order to maintain competitiveness of the 3rd generation mobile communication system in the field of communications, provide users with faster and more personalized mobile communication services with a less delay, and reduce operators' operating costs, the 3rd Generation Partnership Project (3GPP) standard working group is devoting to the research on an Evolved Packet System (EPS). The whole EPS includes an Evolved Universal Terrestrial Radio Access Network (E-UTRAN) and an Evolved Packet Core Networking (EPC), herein the EPC includes a Home Subscriber Server (HSS), a Mobility Management Entity (MME), a Serving GPRS Support Node (SGSN), a Policy and Charging Rule Function (PCRF), a Serving Gateway (S-GW), a PDN Gateway (P-GW) and a Packet Data Network (PDN).
When two User Equipments (UEs) communicate with each other through an EPS, the two UEs need to establish a bearer with the EPS respectively. However, considering the rapid development of the UEs and various mobile Internet services, it is desired to discover and communicate with neighboring UEs for a lot of services, thus creating Device to Device (D2D) services. In addition, the D2D services are also called Proximity-based Services (ProSe). In the D2D services, when two UEs are located close to each other, they can communicate directly and their connected data paths cannot be rounded back to the core network. Thus, on the one hand, the roundabout of data routing can be reduced, and on the other hand, data load of the network can also be reduced.
Currently, the commonly used D2D services include a D2D discovery service. Architecture of D2D discovery service communication is shown in FIG. 1. Two UEs for D2D access can only access an EPC through an E-UTRAN. Both of the UEs may belong to a Public Land Mobile Network (PLMN), or belong to two PLMNs respectively. For a UE, the PLMNs may be divided as a Home PLMN (HPLMN) and a Visited PLMN (VPLMN) when the UE accesses from another PLMN. For a PLMN for an area in which the UE is currently located, it may be collectively referred to as a Local PLMN (LPLMN) regardless of whether the local PLMN is an HPLMN or a VPLMN. In order to realize the D2D discovery service, not only the EPS is deployed on the operator side, but also a ProSe application server which deploys the D2D discovery service is further included. The ProSe application server can be provided by a service provider which operates the D2D service, and can also be provided by a network operator which operates the EPS. A ProSe function is also deployed in a different PLMN.
In the architecture of the D2D discovery service communication, as the UE provides a related ProSe Application (APP), an interface between it and the ProSe application server is a PC1 interface, which provides a related authentication function. An interface between UEs is PC5, which is used for mutual direct discovery and communication between the UEs, and an interface between the UE and the ProSe function is PC3 which is used for discovery authentication through the network. An interface between the ProSe function and an existing EPC is PC4, which includes a user plane interface with the P-GW and a control plane interface with the HSS for discovery authentication of the D2D discovery service. An interface between the ProSe function and the ProSe application server is PC2, which is used for application realization of the D2D discovery service. There are PC6 and PC7 interfaces between ProSe functions respectively, which are used for two cases where the UE is roaming and does not roam respectively. When the UE is roaming, the PC7 interface is used, and when the UE does not roam, the PC6 interface is used. The two interfaces are used for performing information interaction between two ProSe functions when the UE performs D2D discovery service.
In the D2D discovery service, it is divided into an open discovery service and a restrictive discovery service. The open discovery service means that when a user broadcasts a discovery code, any UE can receive the discovery code and discover the user without restriction. The current open discovery service is divided into three processes. In the present disclosure, for convenience of description, UE-A is an announce UE and its corresponding home ProSe function is ProSe Function A, which is referred to as PF-A for short, and UE-B is a monitor UE, and its corresponding home ProSe function is ProSe Function B, which is referred to as PF-B for short. Therefore, the open discovery service is divided into an announce process of the discovered UE-A, and a monitor process of the discovery UE-B. The two processes are processes of initiating a discovery request to corresponding home PFs to acquire allocation of radio resources. Then, the UE-A broadcasts a discovery code, and after receiving the discovery code, the UE-B performs matching for PF-A, which is a matching process. However, for the restrictive discovery service, in the existing technology, the above three processes are still used, and the UE-A will occupy air interface resources at any time to broadcast a discovery code to seek for discovery of the UE-B or other UEs. This will result in a waste of radio resources, which is disadvantageous for the development of the restrictive service.
There is no effective solution to the problem of a waste of radio resources in the restrictive discovery service in the existing technology.